Abstract: The sodium polyaluminates were synthesized by a high temperature solid state method and the luminescence of Eu²⁺
in the sodium polyaluminates was studied. The results show that the structure of the system Na_1+xMg_xAl_11-xO₁₇ from x=0.1 to x=1.0 belongs to Na-beta-alumina and the structure
of the system Na_1.67-2xBa_xMg_0.67Al_10.33O₁₇ changes at about x equal to 0.30, when x is smaller than 0.30 the system forms the solid solution structure of Na-beta-alumina,
when x is larger than 0.30 the system becomes the ordered structure of Ba-beta-alumina, correspondingly the emission peak position and
the relative emission intensity of Eu²⁺ change with the changes of composition and structure of the system. There exist two kinds of the luminescent centers of high and low energies of Eu²⁺ in the
matrix of Na-beta-alumina structure. New phosphor with Ba-beta-alumina structure, Na_0.67Ba_0.50Mg_0.67Al_10.33O₁₇:Eu²⁺,
was obtained.

Key words: sodium polyaluminates, β-alumina structure, europium (Ⅱ) luminescence